EMI filter loading insertion loss automatic test system

Abstract

The invention discloses an EMI filter loading insertion loss automatic test system. The system is characterized in that an upper computer and lower computer structure is adopted, and an upper computer, a signal generator, a data collecting card, a filter test box and a lower computer are included. The system is used for improving efficiency, accuracy and the test speed in filter parameter detection, labor intensity is relieved, test time is saved, a certain intelligent test data analysis and processing function is provided, feedback information of power filter design data is obtained, a filter installation application instruction is provided according to filter performance parameter test data and analysis results, and accordingly a filter can perform the anti-interference performance to the largest extent.

Description

technical field [0001] The invention belongs to the field of electronic measurement and testing, and relates to a power supply EMI loading automatic test system. The test object is a commonly used power supply anti-electromagnetic interference filter. The system realizes its main technical parameters, especially the insertion loss under loading and full load conditions. automatic testing. The system is applied to manufacturers who produce filters for factory inspection, and manufacturers who apply filters for factory inspection. Background technique [0002] Power supply EMI filters are important components for suppressing electromagnetic interference. With the increasingly stringent requirements for electromagnetic compatibility testing and certification, power supply EMI filters are more and more widely used, and the requirements are getting higher and higher. Therefore, it is very important to test the electrical parameters of the power supply EMI filter. The main perfo...

AI Technical Summary

Problems solved by technology

[0006] Manual testing of EMI filter parameters has many shortcomings: first, heavy workload, long test time, slow test speed, low test efficiency, and inaccurate test data, which is not conducive to real-time data analysis and processing, and is not convenient for original The preservation of data cannot establish a sound test database, and it is not convenient for retrospective search and analysis of test data in the future

Second, due to the heavy workload, for large quantities of different types (DC and AC) and different types of filters, it is impossible to test their factory and incoming compliance inspections one by one, and only sampling inspections can be performed. For products with large individual differences, it is difficult to ensure that each filter is qualified in use

Third, for insertion loss, there are differential mode and common mode, and their test configurations and filter connections are also different; it is also necessary to compare impedance matching and mismatching (that is, 50 ohms-0.1 ohms, 50 ohms-100 ohms, 100 ohm-0.1 ohm), which increases the workload and complexity of the test

The test result is also an indirect estimation test, and the important parameter of insertion loss cannot be obtained directly.

Even if the vector network analyzer is used to test the filter insertion loss, there are at least two disadvantages: the instrument is expensive; the instrument storage depth and capacity are limited, and only sporadic test data or drawings can be recorded and saved, and it is impossible to establish a complete large-scale Batch filter characteristic parameter test database

Fourth, for the withstand voltage test in the limit parameters, since the loaded voltage is relatively high, each test must be manually connected and adjusted, which will inevitably make mistakes, and it is not easy to grasp the boosting speed, causing potential harm to the filter under test; It is also easy to cause electric shock damage to the human body, which makes the testers feel resistant, thus perfunctory in this test

[0007] As far as the current automatic test system based on the virtual instrument architecture is concerned, there are also many deficiencies: first, it basically only realizes the automatic test of one parameter of filter insertion loss, and does not realize the automatic test of several main parameters or even all parameters. automated testing of

Second, and more importantly, the filter is only statically tested, that is, the no-load test, and the load test is not implemented.

Third, the insertion loss test under impedance matching and impedance mismatch impedance has not been realized, and this parameter is very important, which is conducive to the user to maximize the use of installation conditions to set a moderate impedance mismatch and greatly improve the filter. Effect

However, at present, many EMI filter manufacturers and users do not have more advanced testing methods and corresponding testing platforms, so that users can only confirm that the insertion loss of filter products does not meet the actual work requirements after discovering problems during use.

As a result, both the manufacturer and the user have borne unnecessary losses, and it has affected the image and reputation of their products and enterprises, and the intangible losses are serious.

Fourth, it has not been networked, and test data cannot be shared in real time

Fifth, the system does not have corresponding intelligence

Sixth, not paying attention to measurement uncertainty and its impact

The present invention automatically tests the main and all electrical parameters of each filter. The only thing that needs to be done manually in the test process is to replace the filter. Because the requirements for parameters such as filter power and current are different, the mechanical structure, package and size of the filter are different. It is different, and the lead wires need to be welded or connected through standard connectors during the test, making it difficult for the automatic feeding mechanism to be suitable for different types of filters, requiring a robot, and its cost and size are too large

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